P1250: TRNA METHYLTRANSFERASE DNMT2 MODULATES GVHD PROCESS VIA TRNA M5C MODIFICATION
Authors: MA Chao, Huanping Guo, Rui Wang, Ting Chen, Yunjing Zeng, Shengwang Wu, Shijie Yang, Yunfang Zhang, XI Zhang
Journal: HemaSphere (2023)

Topic: 21. Stem cell transplantation - Experimental Background: Acute graft versus host disease (aGVHD) is one of the major complications that lead to failure even death after allogeneic hematopoietic stem cell transplantation (allo-HSCT). The immunosuppressive therapy for GVHD treatment is only 50-60% effective and often accompanied by infection, recurrence and organ function damage, makes it a tough clinic problem need to be solved urgently. As an emerging epigenetic regulator, RNA modification plays an important role in the regulation of protein translation, ribosome biosynthesis, cellular process and the occurrence of diseases, however there is little known about the role of RNA modification in the occurrence and development of aGVHD. Aims: To investigate the role of RNA modification in aGVHD development especially in allogenic-T cells and provide a new potential strategies for prevention or treatment of aGVHD from the aspect of RNA modification fields. Methods: Firstly, a mouse aGVHD model was constructed with C57BL/6 (45.1BM and 45.2 T cells) as the donor and Balb/C as the recipient. Secondly, infiltrating T cells in liver and spleen target organs were isolated on day 7 after transplantation and the tRNA modification levels were detected by LC-MS/MS. Finally, the mechanism of RNA modification regulating the occurrence of aGVHD was deeply analyzed by the rescue experiment of RNA modified-related gene knockout mouse with the help of bioinformatics and molecular biology experiments. Results: In this study, based on murine aGVHD model, we found that the tRNA modification profiles of T-cells isolated from aGVHD target organs spleen and liver (7 days post-transplantation) was altered, especially in m6A, m3C, and m5C, were significantly up-regulated. Further analysis showed that the up-regulated level of tRNA m3C and m5C were exist in injected-T (45.2) cells but not the de novo T (45.1) cells isolated from aGVHD group. Western bolt result confirmed that tRNA methyltransferase DNMT2 which responsible for m5C modification, was highly expressed in injected-T (45.2) cells isolated from spleen and liver in aGVHD group. Genetic deletion of Dnmt2 decreased the tRNA m5C modification level in T-cell from spleen. With the rescue experiment, Dnmt2 knockout mice as donor, we found that lack of Dnmt2 in T cell could alleviate the development of aGVHD and the pro-inflammatory cytokines level of IFNγ, TNFα and others were also significantly reduced in serum. In conclusion, our data indicated that Dnmt2-mediated tRNA m5C modification in injected T (45.2) cells was involved in the development of aGVHD. However, the molecular mechanism under Dnmt2-mediated tRNA m5C regulates aGVHD and its impact on immune response need to be further elucidated. Summary/Conclusion: In our study we found that the tRNA modification profiles of T cell isolated from the aGVHD target organs liver and spleen were changed especially in m5C level and the donor T cell lack of functionally DNMT2 could alleviated the aGVHD development, providing a new potential strategies for prevention or treatment of aGVHD from the aspect of RNA modification fields. Keywords: Graft-versus-host disease (GVHD)